Method of pouring steel



Nov. 6, 1928.

F. H. MOYER METHOD OF POURING STEEL Filed Aug. 20, 1926 2 Sheets-Sheet 1Fre dellz'czH/Woyer Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

'FREDELLIA. MOYER, F CANTON, OHIO METHOD or" POURING STEEL.

i Application filed August 20, 1926. Serial N9. 130,517.

The invention relates to a new and novel method of pouring steel and thelike, provided especially for the purpose of cutting down the streamvelocity of the molten metal 6 leaving the ladle nozzle, by a series ofintermediate steps which also remove slag, gas and air from the moltenmetal, pouring clean metal into the mold at minimum velocity and withminimum agitation.

" In the present practice of pouring steel or other molten metals intomolds it is customary to either pour the metal directly fromthe ladlenozzle into the mold, or to pour it through some kind of a pouring boxplaced between the ladle and mold for thepurpose of breaking up orretarding the stream velocity as it enters the mold.

In the first instance, where the pouring box is not used, the highvelocity of the stream of molten metal, due to an initial head ofsome-twelve to fifteen feet in the ladle, causes it to splash when itstrikes the bottom of themold, and as the mold is filled,

gas, air and slag are entrained and forced into the metal, part of thesame remaining in the steel as the ingot solidifies or freezes,

remaining throughout the processing of the material and being found asinclusions and defects in the finished product.

A further disadvantage of the auove method of'pouring is that the moltenmetal which splashes, as it strikes the bottom of the mold, is thrownagainst the side walls of the mold, adhering thereto and forming scabsor surface defects in the surface of the ingot being poured. Thesedefects become imbedded in the surface of the steel, when re duced insize in a rolling mill, and must be removed before further processing asthey will otherwise appear in the surface of the finishedbar or otherproduct.

This operation is very costly as each piece must be inspected and thesedefects chipped or ground therefrom in order to insure a satisfactorysurface in the finished product, as require .In order to reduce thestream velocity of the. molten metal entering the mold, pouring boxes,as above referred to, have been used to receive the molten metalfrom-the ladle nozzle and pour the same into the mold.

Various types of these boxes have been used whereby the depth of themetal is considerably reduced by the regulation of the incoming streamfrom the ladle into the pouring box, in order to establish apredetermmed relatively low head, a suitable noz zle and stoppermechanism being provided 1n the pouring box whereby the metal can beteemed or poured into the mold under this low velocity head.

As the pouring of the molten metal from the ladle progresses, thevelocity ead decreases, while the velocity head in the pourmg boxremains substantially constant, producing an ideal condition under whichto fill the molds.

Such pouring boxes, however, are extremely small in volume as comparedwith the volume of metalwhich is to pass therethrough 1n a given time,and furthermore, no means have beenprovided in these pouring boxes foreliminating gas and slag or for preventing the churning effect of thesteel, slag, gas and air due to the velocity of the incoming moltenmetal; these boxes being so formed that the molten metal together withthe slag, gas and air carried therein, is agitated as it isreceived intothe pouring box and poured therefrom.

The small volume of these pouring boxes makes it impossible to maintaina constant flow of metal into and out of the box, as is required in goodpouring practice and also makes it impossible to quiet the metal downdunn its passage through the pouring box into the mold.

Thus the elimination from the steel of gas, slag and entrained air, isnot accomplished with these pouring boxes.

.The agitating action, above referred to, may be well illustrated byholding a glass under a water faucet and turning the water on fullforce. It will be seen that there is a great swirling action of water inthe glass as it overflows and upon shutting off the water quickly, theglass will not be entirely filled owing to the combined swirling actionof the water and the entrained air bubbles. forced into the water by thevelocity of the incoming water from the faucet. As soon as the water isshut olf this action ceases and leaves the glass only partially filled.

The improved process to which this invention pertains may be used inconjunction with the present method of receiving the molten metal fromthe ladle into which the metal has been tapped directly from thefurnace, through the usual tapping spout; or it may be used inconjunction with the improved slag and gas eliminator disclosed in myapplication for Letters Patent Serial No. 124,609, filled July 24, 1926,in which latter case the results obtained will produce much cleanersteel than the old method of running the slag and steel directly intothe ladle.

The object of the present improvement is to provide a method of pouringsteel which will overcome the above mentioned objections present in theordinary methods of pouring steel.

The aboveand other objects may be attained by providing a processwherein the molten metal poured from the ladle will be received in oneportion of a vessel designed to receive and break the stream velocity ofthe incoming molten metal and to absorb splash and agitation causedthereby preliminary to passing to an adjacent comparatively largereservoir portion of the vessel.

This reservoir is arranged to receive the partially separated mixture ofmetal, slag, gas andentrained air, from the receiving portion of thevessel, by passing or overflowing over a dam or weir which is preferablyof sufiicient width to permit a wide and shallow stream of metal to passthereover from one portion of the vessel to the next succeeding portion.

As the metal flows over this dam it presents a comparatively largesurface area, thereby permitting the mixture of metal, slag, as and air,of shallow depth, and enlarge area, to become separated on account ofthe difference in specific gravity of the several materials, the metalbeing thereby deslagged and de-gasified.

The molten metal being the heaviest will settle to the bottom, the-gasand air will be released into the atmosphere and the slag particles willrise to the top and float upon the surface. The top of the dam is spacedabove the bottoms of the receiving and reservoir portions of the vessel,precluding further agitation of the metal inthe reservoir portion.

This reservoir portion of the vessel is of a considerably enlarged area,thus retarding, changing or slowing down the rate of flow of the metal,and of suflicient depth to produce the desired pressure and potentialhead for pouring or teeming into molds, as this depth determines thevelocity of the stream entering the molds.

The volume of this reservoir is such that during the pouring or teemingthe metal will be collected and remain in the reservoir a comparativelylong time as compared with the usual pouring box' practice. There aretwo reasons for this, first, having a large volume, for instanceone-fifth of the capacity of a ladle containing one hundred tons ofmolten metal requiring a teeming time of forty-five to sixty minutes; atthis rate with the reservoir containing twenty tons, the metal willrequire from nine to twelve minutes to pass therethrough', and is soretarded that practically all gas,.air and slag, remaining with themetal, separates out leaving the purified metal in the lower portion ofthe reservoir from which it can be drawn as required.

The second reason is that having a large body or volume of metal fromwhich to'draw in teeming, a practically constantly teeming head ismaintained, as the volume of metal being withdrawn is small inproportion to the volume in the reservoir portion.

The metal may be poured or teemed directly from the reservoir into themolds but, for reasons which will later appear, it is preferable towithdraw the metal from the large body in the reservoir into anotherportion or compartment to form a small body of metal from which themetal is teemed or poured, this teeming compartment communieating withthe lower portion of the reser-i voir through a shallow comparativelywide opening to prevent the passage of slag into the teemingcompartment.

The improved method may be carried out. by means of the apparatusillustrated in the accompanying drawings, in which Figure 1 is alongitudinal sectional view of the pouring device by the use of whichthe improved method is accomplished, showing the same mounted inposition to receive molten metal from the ladle and pour the. same intoan ingot mold;

Fig. 2, a sectional elevation on the line 22, Fig. l;

Fig. 3, a plan view of the same, and

Fig 4, a sect-ion on the line 44, Fig. 1.

Similar numerals of reference indicate corresponding parts throughout.the drawings.

In carrying out the improved method a pouring device is interposedbetween the ladle l and the mold 2, this pouring device comprising areceptacle indicated generally at 3.

The ladle is adapted to receive the molten metal either directly fromthe furnace in theusual manner, or. from the slag and gas eliminatordisclosed in my co-pending application above referred to, and may beprovided with the usual pouring nozzle 4 and stopper mechanism 5 forcontrolling the same.

The ingot mold 2 may be of the usual construction and carried upon a car6 mounted upon tracks 7 located adjacent to the usual pouring platform8, all of which may be of usual and well lmown construction as adaptedto present pouring practice.

The pouring device may comprise the steel shell 10 lined with suitablerefractory material 11 and-carried upon a car 12 mounted on tracks, 13,located parallelto the tracks 7. The vessel 3 may comprise the largecentral reservoir 14 covered as by the lid 15 provided with the centralgas outlet 16; the receiving compartment 17 communicating with one sideof the reservoir through the wide neck 18 spaced above the bottoms ofboth of said compartments and forming a dam between the same; and thepouring compartment 19 which may be closed upon its top by the cover 19-and is provided with the pouring nozzle 20 controlled by a stopper 21arran ed to be operated as by the lever 22 extended across the pouringplatform in a position to be accessible to workmen thereon.

The lower portion of the pouring compartment communicates with the lowerpor tion of the body of metal in the reservoir through the reducedopening 23, permitting the molten metal to pass from the bottom of thereservoir into the pouring compartment, and itsrate of flow to bespeeded up in passing through the opening 23.

The receiving compartment 17 is of sufficient volume to receive andbreak the velocity of the molten metal received from the nozzle of theladle, the splash and churning or boiling action of'the ladle streambeing absorbed in'this compartment as the molten metal is receivedtherein from the ladle.

The metal is thus considerably quieted before it reaches the receivingcompartment, and when the same is filled to the height of the dam themolten metal passes through the opening 18 in a thin sheet of relativelygreat width and length as compared to thickness at a very much reducedvelocity due to the width ofthe opening 18.

As this opening is of some considerable length also the molten metalpassing thereover in a thin sheet is given a chance to rid itself of thegas and entrained air bubbles which rise to the surface and escape inthe atmosphere, the slag also coming to the surface of the molten metalas it flows into the reservoir compartment 14.

Since this reservoir is 'of relatively large area and shallow depth andthe metal passes quietly into the same, from the receiving compartment,the action of the molten mass of metal is further retarded therein.

The stopper 21 in the teeming or pouring compartment remains closedduring the time that the reservoir is being filled, permitting theincoming molten metal to rise, in both the reservoir and pouringcompartment, to the desired level, preferably two or three inches abovethe bottom of the neck 18,between the receiving compartment andreservoir. During this period of filling of the reservoir and pouringcompartment, gas will continueto rise to the surface in the reservoirand slag will riseto the surface in both the reservoir and pouringcompartment until the metal rises above the to of the opening llberetained on the surface of the metal in the reservoir prove the only,excepting such slag which has already passed into the pouringcompartment and formed a blanket on the top of the metal therein. Inlets25 may be provided in the reservoirand pouring compartment both,.for thepurpose of introducing a suitable agent, to form a non-oxidizingatmosphere over all exposed surfaces. Since the level of the molten massis kept below the top of the neck 18, the receivin compartment 17 willalso receive thebene t of this non-oxidizing atmosphere, and in order toconserve heat of the metal and prevent oxidizing a cover may be providedfor the receiving compartment also.

When the reservoir and pouring compartment have been filled to thedesired level above mentioned, the stopper 21 is opened and the metal isteemed into the molds in the usual manner. No further slag can enter thepouring compartment from the reservoir, only clean meta, free of gas,slag and air passing through the teeming nozzle 20 into the molds.

As the last ingots are poured it will be necessary to watch theoperation carefully and when the slag remaining in the reservoir startsto pass into the pouring compartment the stopper 21 should be closed andthe slag drained into a slag pot or other suitable receptacle in usualmanner so that only clean metal will be poured into the molds.

This improved method is especially adapted for the making of steelswhere internal and surface cleanliness are of the h'ghest importance;and it will not only imabove qualities of the steel, but, will alsomaterially increase the yield over pre'sent practice, due to theelimination of gases and slag from the steel, the uniformity of pouringand the minimizing of the splash and churning of the steel in the molds.

This method of pouringsteel will be effective for sheet bars in theminimizing of the cause of blisters in the finished sheets; and also insteels known to the trade as high grade steels for forging and otheruses where a clean steel is required.

Hot tops may be used upon the molds as in common practice or if desiredthey may be eliminated, a very good quality of ingot being produced inthe mold with this method, without the use of hot tops.

Although ideal results are obtained by this method by passing the moltenmetal through three communicating compartments, in the pouring vessel,it should be understood that the objects of the invention, may beaccomplished by providing only two compartmentsor even by providing onlya single compartment of sufiicient area to quiet the molten metal andpermit degasification between the receiving and pouring ends of thecompartment. Attention is also called to the fact that the pouringvessel may be provided withone or more pouring nozzles arranged tosimultaneously pour into a like number of molds at one setting.

The apparatus disclosed in this application for carrying out the hereindescribed method is described and claimed in a copending application,filed August 17, 1926, Serial No. 129,806.

I claim i I l. The method of pouring molten metal which consists inpouring and receiving the metal in an oxidizing atmosphere, de-gasifyingthe metal in a non-oxidizing atmosphere, and then teeming the metal inan oxidizing atmosphere. I

2. The method of pouring molten metal which consists in pouring andreceiving the metal, de-slagging the metal, and then teeming the metal,the body of metal having the same potential head throughout thereceiving de-slagging and teeming operations.

3. The method of pouring the molten metal which consists in pouring andreceiving the metal in an oxidizing atmosphere, changing the rate offiow of metal in a nonoxidizing atmosphere, and then teeming the metalin an oxidizing atmosphere.

4:. The method of pouring molten metal which consists in pouring andreceiving the metal in an oxidizing atmosphere, changing the rate offlow of metal in a non-oxidizing atmosphere, and then teeming the metalin an oxidizing atmosphere, the body of metal having the same potentialhead throughout the receiving, change of rate of flow and teemingoperations.

5. The method of purifying molten metal which consists in pouring andreceiving the metal, passing the metal in a thin sheet of relativelygreat width and length as compared to thickness, and then teeming themetal, the body of metal having the same potential head throughout thereceiving, passing and teeming operations.

6. The method of purifying molten metal which consists inpouring andreceiving the metal, overflowing the metal in a thin sheet of relativelygreat Width and length as compared to thickness, changing the rate offlow of the metal, and then teeming the metal, the body of metal havingthe same potential head throughout the receiving, overflowing, change ofrate of flow and teeming operations.

7. The method of purifying molten metal which consists in pouring andreceiving the metal, overflowing the metal in a thin sheet of relativelygreat width and length as compared to thickness, slowing down the rateof flow of the metal, speeding up the rate of flow of the metal, andthen teeming the metal, the body of metal having the same potential headthroughout the receiving, overflowing, slowing dowm speeding up andteeming operations.

8. The method of purifying molten metal which consists in pouring andreceiving the metal, overflowing the metal in a thin sheet of relativelygreat width and length as compared to thickness, slowing down the rateof flow of the metal, and then Withdrawing the metal from the lowerportion of the body of metal, the body of metal having the samepotential head throughout the receiving, overflowing, slowing, down andWithdrawing operations.

9. The method of purifying molten metal l metal, passing the metal in athin sheet of relatively great width and length as compared tothickness, collecting the metal in a large body, and then teeming themetal, the metal having the same potential head throughout thereceiving, passing, collecting and teeming operations.

11. The method of pouring molten metal which consists in passing themetal in a thin sheet of relatively great width and length as comparedto- .thickness, collecting the metal in a. large body, withdrawing themetal from a lower portion of the body, and then teeming the metal, themetal having the same potential head throughout the passing, collecting,withdrawing and teeming operations.

12. The method of pouring molten metal which consists in passing'themetal in. a thin sheet of relatively great width and length as comparedto thickness, collecting the metal in a large body, withdrawing themetal from a lower portion of tli'e large body to a small "body ofmetal, and then teeming the metal from a lower portion" of the smallbody, the'metal having the same potential head throughout the passing,collecting, withdrawing andteeming operations.

13. The method of pouring molten metal which consists in pouring andreceiving the .metal, overflowing the metal in a thin sheet ofrelatively great width and length as compared to thickness, collectingthe metal in a large body, withdrawing the metal from below the surfaceof the large body, and then teeming the metal, the metal having the samepotential head throiighout the receiving, overflowing, collecting,Withdrawing and teeming operations.

14. The method of pourin molten metal which consistsin pourmg anreceiving the metal, overflowing the metal in a thin sheet of relativelygreat width and length as compared to thickness, collecting the metal ina large body, withdrawing the metal from below the surface of the largebody to a small body of metal, and then teeming the metal from below thesurface of the small body, the metal having the same potential headthroughout the receiving, overflowing, collecting, Withdrawing andteeming operations.

15. The method of ouring molten metal which consists in pouring andreceiving the metal, de-gasifying the metal, and then teeming the metal,the body of metal having the same potential head throughout thereceiving, de-gasifying and teeming operations.

16. The method of pouring molten metal which consists in pouring andreceiving the metal, de-gasifying and de slagging the metal and thenteeming the metal, the body of metal having the same potential headthroughout the receiving, de-gasifying, desla ging and teemingoperations.

1 The method of conveying molten metal from a ladle to a mold whichconsists in collecting the metal from the ladle in a large body,permitting the gases to-escape from the metal, skimming the slag fromthe metal, withdrawing the metal from below the surface of the largebody to a small body, and then teeming the metal, the metal having thesame potential head throughout the collecting, escaping, skimming,withdrawing and teeming operations.

In testimony that I claim the above, I have hereunto subscribed my name.

FREDELLIA H. MOYER.

